SFCXX1 - SFCXX2 Air Flow Testing Report

Field Service Report

SFCXX1 / SFCXX2

Air Flow Testing Report

Flow Control Facilities

Completed by

David List

On behalf of CLIENT

July, 2016

Employed by Ventia

Work Order XXXXXXX


SFCXX1 / SFCXX2 Flow Control Facility


The aim of this report is to outline the procedure taken to identify the correct flow

rates through the odour filters. Then identify some improvements that “CLIENT” may

wish to implement to improve performance.

Contents

Work Order Request ........................................................................................................................ - 1 -

Air Flow Testing Procedure ............................................................................................................ - 3 -

Testing Device .............................................................................................................................. - 3 -

Testing Method ............................................................................................................................. - 4 -

Testing Procedure ........................................................................................................................ - 5 -

SFCXX1 ............................................................................................................................................. - 6 -

As Constructed ............................................................................................................................. - 6 -

Test Results .................................................................................................................................. - 7 -

Conclusion ..................................................................................................................................... - 7 -

SFCXX2 ............................................................................................................................................. - 8 -

As Constructed ............................................................................................................................. - 8 -

Test Results .................................................................................................................................. - 9 -

Conclusion ..................................................................................................................................... - 9 -

Improvements ................................................................................................................................. - 10 -

Odour Control Pre-Filters .......................................................................................................... - 10 -

SFCXX1 Pre-Filters ............................................................................................................... - 11 -

SFCXX2 Pre-Filters ............................................................................................................... - 12 -

Airepure Australia ................................................................................................................... - 13 -

Differential Pressure Transmitter ............................................................................................. - 14 -

Air Flow Transmitter ................................................................................................................... - 14 -

Conclusion ....................................................................................................................................... - 15 -

References ...................................................................................................................................... - 15 -

Enquiries .......................................................................................................................................... - 16 -


- 1 -

Work Order Request The following is a direct exert from an email sent by “CLIENT” to “VENTIA”;

From: CLIENT (EMAIL)

Sent: Tuesday, 31 May 2016 11:38 AM

To: VENTIA (EMAIL)

Subject: Work order 6345599

Hi VENTIA,

I am currently looking at replacing the carbon filter media at SFCXX1 and SFCXX2. To ensure that we

order the correct amount of carbon we need to know the air speeds through the carbon beds. Can you

please arrange for the following tests so that we can confirm airflows?

SFCXX1:

Confirm what speed fan runs at, either run fan and take reading or confirm speed with manufacturer.

Measure airflow prior to fan without fan running. This is so we can see what passive airflows are experienced on site. (If we have adequate airflow we will decommission the fan)


- 2 -

SFCXX2:

Confirm what speed fan runs at, either run fan and take reading or confirm speed with manufacturer.

Measure airflow prior to fan without fan running. This is so we can see what passive airflows are experienced on site. (If we have adequate airflow we will decommission the fan)

Note that passive readings will need to be taken while the wet well pumps are not in operation.

If you have any questions, please let me know.

Regards,

CLIENT

Sewer Optimisation Technician

Lucknow St, Mitcham, Victoria 3132


- 3 -

Air Flow Testing Procedure To achieve accurate flow rates, the right testing equipment and procedure must be

used.

Testing Device

The device chosen was the FLUKE 922 Air Flow Tester.

The FLUKE 922 combined with the pitot tube is

capable of measuring “Velocity” and “Flow”.

The particular method that was used during the

testing is “Flow”. The flow unit used are m3/h.

Of course the flow values given in the testing are

directly related to velocity and can be converted via

the link below;

Air Flow Conversion

The table below shows the function and capabilities of the Fluke 922;

Please see full details in data sheet attached to this PDF.

http://www.comairrotron.com/airflow-unit-conversion


- 4 -

Testing Method

Air flow readings can be inaccurate due to small eddies and currents forming within

the flow path. More commonly referred to as “Turbulent” & “Laminar” flow, see

below;

To ensure that accurate readings are achieved, the pitot tube is traversed across the

depth of the pipe and then averaged over the sample time.

Traversing is a method where the measuring instrument is moved across the flow

path to ensure all flows can be measured accuracy. See below;

For more information on pitot tubes and traversing, please see link below;

Performing a Duct Traverse

https://www.youtube.com/watch?v=TiuyRpPWgbQ


- 5 -

Testing Procedure

To ensure that all bases were covered, several tests were performed at different

operational times.

1. Ensure negative or neutral air flow

INLET - Pump ON, Extraction Fan OFF

OUTLET - Pump ON, Extraction Fan OFF

2. Ensure positive passive air flow

INLET - Pump OFF, Extraction Fan OFF

OUTLET - Pump OFF, Extraction Fan OFF

3. Confirm extraction air flow

INLET - Pump OFF, Extraction Fan ON

OUTLET - Pump OFF, Extraction Fan ON

All tests had a sample time of 1-minute. The MAX, MIN & AVERAGE readings were

then recorded. See example below;

NOTE: An accurate flow rate is achieved by combining the velocity with the diameter

of the pipe or duct. For each sample table I will list the size of the pipe so

conversions can be made if necessary.


- 6 -

SFCXX1

As Constructed

Before conducting the air flow tests I contacted the manufacturer for the as

constructed drawings.

Aerotech were able to provide me with the original specifications to the extraction

fan, including the operating flow rate of 3510 m3/h @ 1.4KPa. See below;

The motor specifications were also confirmed via the name plate. See below;

See the full “AS CONS” attached to this PDF.


- 7 -

Test Results

For each of the tests below the following applies;

Inlet Diameter = 500mm

Outlet Diameter = 400mm

Units = m3/h (cubic meters per hour)

Sample Time = 1 min (approximately)

Pump ON, Extraction Fan OFF

MAX MIN AVERAGE INLET 0 0 0

OUTLET 0 0 0

Pump OFF, Extraction Fan OFF


OUTLET 607 573 590

Pump OFF, Extraction Fan ON


OUTLET 3168 2054 2721

Conclusion

The readings above indicate that there is positive air flow through filter when the

pumps are OFF. Whether they are adequate for the new media cannot be confirmed.

The static outlet pressure, on TEST 3 was 170 Pa.

Whilst the specifications suggest the air flow is 3510

m3/h @1.4 KPa, this does not mean that it will operate

at 1.4 KPa.

The low operating pressure could mean that the media

install is just porous in nature. This could also indicate

that the pre-filters are blocked.


- 8 -

SFCXX2

As Constructed

Before conducting the air flow tests I contacted the manufacturer for the as

constructed drawings.

Aerotech were able to provide me with the original specifications to the extraction

fan, including the operating flow rate of 1000 m3/h @ 1.4KPa. See below;

The motor specifications were also confirmed via the name plate. See below;

See the full “AS CONS” attached to this PDF.


- 9 -

Test Results

For each of the tests below the following applies;

Inlet Diameter = 230mm

Outlet Diameter = 230mm

Units = m3/h (cubic meters per hour)

Sample Time = 1 min (approximately)

TEST 1 - Pump ON, Extraction Fan OFF


OUTLET 0 0 0

TEST 2 - Pump OFF, Extraction Fan OFF


OUTLET 149 99 127

TEST 3 - Pump OFF, Extraction Fan ON


OUTLET 812 677 747

Conclusion

The readings above indicate that there is positive air flow through filter when the

pumps are OFF. Whether they are adequate for the new media cannot be confirmed.

The static outlet pressure, on TEST 3 was 153 Pa. Whilst

the specifications suggest the air flow is 1000 m3/h @1.4

KPa, this does not mean that it will operate at 1.4 KPa.

The low operating pressure could mean that the media

install is just porous in nature. This could also indicate that

the pre-filters are blocked.

NOTE: I suspect that the INLET readings for TEST 3 were

compromised. I would suggest the more relevant reading

are from the OUTLET.


- 10 -

Improvements

Odour Control Pre-Filters

Ensuring that the pre-filters are working efficiently is an essential part of the odour

control operation. The ideal installation would be as follows;

The first filter is a “Mist Eliminator”. This separates oil and water from the air, then

the condensate is exhausted via the drain.

The second filter is a “Particle Filter”. This further filters any large particles that are

not caught by the mist eliminator.

If these filters are not operating effectively, they can allow moisture to enter the filter

media a dramatically shorten its life span. A blocked pre-filter can also dramatically

reduce the permissible air flow.

To avoid excessive moisture, the condensation drain should be adequately

maintained so that water does not pool in the bottom of the duct.


- 11 -

SFCXX1 Pre-Filters

The pre-filters for SFCXX1 feature only one

set of “Mist Eliminators”. I suggest the

missing filter was removed because of

possible back pressure issues or was

simply not replaced.

The “Mist Eliminator” is very dirty. It can be

washed but I suggest it be replaced.

The differential pressure across the pre-

filter was measured whilst the exhaust fan

was running. The reading was 1168 Pa.

With a clean filter you should only get a few

hundred pascals at the most. Suggesting it

is very blocked.


- 12 -

SFCXX2 Pre-Filters

The pre-filters for SFCXX2 do not feature

“Mist Eliminators” and are visibly corroded.

These filters are called “V FORM” and are

acceptable if properly maintained. They are

designed to be “throw away” items.

Like the filter at SFCXX1, these filters are

also very dirty. The picture shows a

replacement date of the 26/9/14. They

should be replaced at least every 6

months.

The differential pressure across the pre-filter

was measured whilst the exhaust fan was

running. The reading was 986 Pa.

With a clean filter you should only get a few

hundred pascals at the most. Suggesting that

they are very blocked.


- 13 -

Airepure Australia

Airepure was the company that installed the Odour Filters. I got in contact with Allan

Heckenberg who replied to me via email with the following suggestions;

Hi David,

Good chatting to you. Managed to find the data sheets pretty swiftly.

Data for the mist eliminators and Vform filters attached, see pressure drops for “new”. Fouled these

numbers should increase by about 150Pa at normal flow rates.

Given the pictures, I would change the V forms, and try to give the mist eliminators a power wash, if

they are not good, re-use till you can obtain some new ones from us. They are overseas units, so

figure about 10 weeks from order. The V form disposables are generally ex stock or a week at worst,

a bit longer for SST versions.

You would normally dump the pre filters every six months or so, the mist eliminators when they don’t

respond well to cleaning.

Media is expensive, but you get the performance life you pay for. Pressure drop across the bed

should be essential constant over time, even when exhausted chemically. Assuming the bed has not

been grossly contaminated by the pre filters failing – due to lack of maint.

Always happy to chat to the design folks, we can always offer a range of price points that actually

work, and let you know up-front the up and down sides of any of the media and solutions.

Cheers,

Dr Allan Heckenberg (PhD)

Business Manager

Airepure Australia Pty Ltd

64 Geddes Street, Mulgrave VIC 3170

PO Box 747, Mulgrave VIC 3170

www.airepure.com.au

See the full email and filter data sheets attach to this PDF.

http://www.airepure.com.au/


- 14 -

Differential Pressure Transmitter

I would suggest installing a differential pressure transmitter across the pre-filters.

Shown below is an ABB 266DSH Differential Pressure Transmitter;

By installing and monitoring the differential pressure across the pre-filters you will be

able to capture when the filters need replacing.

For further information, see link below;

ABB 266 Differential Pressure Transmitter - Data Sheet

Air Flow Transmitter

I would suggest installing an air flow sensor on the outlet pipe. Shown below is an

IFM SA4100 Flow Transmitter.

By installing and monitoring the air flow you can accurately identify if the correct

amount of air is being exhausted.

For more information, see link below;

IFM SAF4100 Flow Transmitter - Data Sheet

https://library.e.abb.com/public/8b957e56d4984927b8ca9d4d4bc4352e/DS_266DSH-EN_H.pdf

http://www.ifm.com/products/uk/ds/SA4100.htm


- 15 -

Conclusion The results show that both at SFCXX1 and SFCXX2 “Odour Filters” can operate

passively.

Though if this were to be introduced considerations would have to be made in

regards to the lack of air flow. By reducing the air flow this may have other corrosive

effects on the exposed equipment in the wet well (guide rails, pumps, chains etc).

I would suggest trailing the new passive odour control before remove any existing

equipment.

References The following documentation is attached to this PDF;

No References (CENSORED)


- 16 -

Enquiries Should you need any clarification on this document or if you wish to discuss

implementing any suggested improvements contact myself or Anthony Crowther.

David List Mob: 0408 006 344 Email: [email protected] Anthony Crowther Mob: XXXX XXX XXX Email:

Engineering

SFCXX1 - SFCXX2 Air Flow Testing Report